:root {
  --ink: #20242a;
  --muted: #66707a;
  --paper: #f4f5f1;
  --white: #ffffff;
  --line: #cfd4d3;
  --red: #e84d3c;
  --mint: #43a982;
  --blue: #3973c8;
  --rail: min(1120px, calc(100% - 48px));
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
  letter-spacing: 0;
  line-height: 1.7;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  width: 100%;
  border-bottom: 1px solid var(--line);
  background: rgba(244, 245, 241, 0.96);
}

.header-inner {
  width: var(--rail);
  min-height: 68px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 800;
}

.brand img {
  width: 38px;
  height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav a {
  min-height: 40px;
  padding: 7px 14px;
  border-bottom: 2px solid transparent;
  font-size: 14px;
  font-weight: 700;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  border-color: var(--red);
  color: var(--red);
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--white);
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  height: 2px;
  margin: 4px 0;
  background: var(--ink);
}

.download-link {
  display: inline-flex;
  min-width: 112px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--ink);
  border-radius: 6px;
  background: var(--ink);
  color: var(--white);
  font-size: 15px;
  font-weight: 800;
}

.download-link:hover {
  border-color: var(--red);
  background: var(--red);
}

.text-link {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  border-bottom: 2px solid var(--ink);
  font-weight: 800;
}

.hero {
  border-bottom: 1px solid var(--line);
  background: var(--white);
}

.hero-inner {
  width: var(--rail);
  min-height: 590px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.04fr) minmax(380px, 0.96fr);
  align-items: center;
  gap: 56px;
  padding: 38px 0 42px;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  color: var(--red);
  font-size: 13px;
  font-weight: 900;
}

.eyebrow::before {
  width: 34px;
  height: 2px;
  content: "";
  background: var(--red);
}

.hero h1 {
  max-width: 600px;
  margin: 0;
  font-size: 52px;
  line-height: 1.12;
  letter-spacing: 0;
}

.hero-copy > p {
  max-width: 610px;
  margin: 20px 0 0;
  color: var(--muted);
  font-size: 17px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 22px;
  margin-top: 24px;
}

.mode-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 25px;
}

.mode-row span {
  padding: 5px 9px;
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--muted);
  background: var(--paper);
  font-size: 12px;
  font-weight: 700;
}

.instrument-frame {
  position: relative;
  min-height: 500px;
  display: grid;
  place-items: center;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--paper);
}

.instrument-frame::before,
.instrument-frame::after {
  position: absolute;
  border: 1px solid var(--line);
  border-radius: 50%;
  content: "";
}

.instrument-frame::before {
  width: 390px;
  height: 390px;
}

.instrument-frame::after {
  width: 458px;
  height: 458px;
  border-style: dashed;
}

.instrument-frame img {
  position: relative;
  z-index: 2;
  width: 240px;
  max-width: 400px;
  border: 8px solid var(--white);
  box-shadow: 0 18px 42px rgba(32, 36, 42, 0.18);
}

.dial-index {
  position: absolute;
  z-index: 3;
  right: 16px;
  top: 16px;
  width: 96px;
  padding: 9px 10px;
  border-left: 4px solid var(--red);
  background: var(--white);
  font-size: 12px;
  font-weight: 800;
  line-height: 1.4;
}

.hero-tick {
  position: absolute;
  z-index: 3;
  left: 16px;
  bottom: 16px;
  color: var(--muted);
  font-family: Consolas, monospace;
  font-size: 12px;
}

.section {
  padding: 78px 0;
}

.section.alt {
  background: var(--white);
}

.section-inner {
  width: var(--rail);
  margin: 0 auto;
}

.section-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 30px;
}

.section h2 {
  margin: 0;
  font-size: 34px;
  line-height: 1.2;
}

.section-code {
  color: var(--red);
  font-family: Consolas, monospace;
  font-size: 13px;
  font-weight: 800;
}

.snapshot-band {
  padding: 34px 0;
  border-bottom: 1px solid var(--line);
  background: var(--ink);
  color: var(--white);
}

.snapshot-inner {
  width: var(--rail);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 0.8fr repeat(3, 1fr);
  align-items: stretch;
}

.snapshot-band h2 {
  margin: 0;
  align-self: center;
  font-size: 28px;
}

.snapshot-item {
  padding: 10px 22px;
  border-left: 1px solid #515860;
}

.snapshot-item strong,
.snapshot-item span {
  display: block;
}

.snapshot-item strong {
  font-size: 16px;
}

.snapshot-item span {
  color: #b8c0c7;
  font-size: 13px;
}

.path-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.path-step {
  min-height: 205px;
  padding: 28px;
  border-right: 1px solid var(--line);
}

.path-step:last-child {
  border-right: 0;
}

.path-number {
  color: var(--red);
  font-family: Consolas, monospace;
  font-size: 13px;
  font-weight: 900;
}

.path-step h3 {
  margin: 28px 0 8px;
  font-size: 21px;
}

.path-step p {
  margin: 0;
  color: var(--muted);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.feature-item {
  min-height: 190px;
  padding: 28px;
  background: var(--white);
}

.feature-marker {
  width: 18px;
  height: 18px;
  border: 4px solid var(--blue);
}

.feature-item:nth-child(2) .feature-marker {
  border-color: var(--mint);
  border-radius: 50%;
}

.feature-item:nth-child(3) .feature-marker {
  border-color: var(--red);
  transform: rotate(45deg);
}

.feature-item:nth-child(4) .feature-marker {
  border-color: var(--ink);
}

.feature-item h3 {
  margin: 22px 0 8px;
  font-size: 21px;
}

.feature-item p {
  margin: 0;
  color: var(--muted);
}

.gallery-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
  align-items: start;
}

.screen-item {
  min-width: 0;
  border-top: 4px solid var(--ink);
  padding-top: 16px;
}

.screen-item:nth-child(2) {
  border-color: var(--mint);
}

.screen-item:nth-child(3) {
  border-color: var(--red);
}

.screen-item img {
  width: 100%;
  max-width: 400px;
  aspect-ratio: 336 / 598;
  object-fit: contain;
  background: var(--paper);
}

.screen-item h3 {
  margin: 16px 0 4px;
  font-size: 18px;
}

.screen-item p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.faq-preview {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 60px;
  align-items: start;
}

.faq-preview h2 {
  margin-bottom: 18px;
}

.faq-preview p,
.faq-lead {
  color: var(--muted);
}

.faq-lead {
  margin: 0 0 16px;
}

.question-list {
  border-top: 1px solid var(--line);
}

.question-row {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 14px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.question-row b {
  color: var(--red);
  font-family: Consolas, monospace;
}

.question-row h3 {
  margin: 0 0 5px;
  font-size: 17px;
}

.question-row p {
  margin: 0;
  font-size: 14px;
}

.cta-band {
  padding: 54px 0;
  background: var(--red);
  color: var(--white);
}

.cta-inner {
  width: var(--rail);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}

.cta-inner h2 {
  margin: 0 0 5px;
  font-size: 30px;
}

.cta-inner p,
.cta-copy {
  margin: 0;
}

.cta-inner .download-link {
  border-color: var(--white);
  background: var(--white);
  color: var(--ink);
}

.page-hero {
  padding: 72px 0 60px;
  border-bottom: 1px solid var(--line);
  background: var(--white);
}

.page-hero-inner,
.article-layout {
  width: var(--rail);
  margin: 0 auto;
}

.page-hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 60px;
  align-items: end;
}

.page-hero h1 {
  max-width: 780px;
  margin: 0;
  font-size: 46px;
  line-height: 1.16;
}

.page-hero p {
  max-width: 750px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 17px;
}

.page-index {
  padding: 18px;
  border: 1px solid var(--line);
  border-left: 5px solid var(--blue);
  background: var(--paper);
}

.page-index strong,
.page-index span {
  display: block;
}

.page-index span {
  color: var(--muted);
  font-size: 13px;
}

.article-layout {
  padding: 64px 0 80px;
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  gap: 64px;
  align-items: start;
}

.article-nav {
  position: sticky;
  top: 96px;
  border-top: 4px solid var(--ink);
}

.article-nav a {
  display: block;
  padding: 12px 4px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.article-nav a:hover {
  color: var(--red);
}

.prose {
  min-width: 0;
}

.prose section {
  scroll-margin-top: 96px;
  padding-bottom: 48px;
  margin-bottom: 48px;
  border-bottom: 1px solid var(--line);
}

.prose section:last-child {
  margin-bottom: 0;
}

.prose h2 {
  margin: 0 0 22px;
  font-size: 30px;
}

.prose h3 {
  margin: 26px 0 10px;
  font-size: 20px;
}

.prose p,
.prose li {
  color: #4f5962;
}

.prose ul,
.prose ol {
  padding-left: 22px;
}

.note {
  margin: 24px 0;
  padding: 18px 20px;
  border-left: 5px solid var(--mint);
  background: var(--white);
}

.note strong {
  display: block;
  margin-bottom: 4px;
  color: var(--ink);
}

.guide-rail {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 24px 0;
}

.guide-rail div {
  padding: 18px;
  border: 1px solid var(--line);
  background: var(--white);
}

.guide-rail b,
.guide-rail span {
  display: block;
}

.guide-rail b {
  color: var(--red);
  font-family: Consolas, monospace;
}

.faq-stack {
  display: grid;
  gap: 12px;
}

.faq-stack details {
  border: 1px solid var(--line);
  background: var(--white);
}

.faq-stack summary {
  position: relative;
  min-height: 58px;
  padding: 16px 48px 16px 18px;
  cursor: pointer;
  font-weight: 800;
  list-style: none;
}

.faq-stack summary::-webkit-details-marker {
  display: none;
}

.faq-stack summary::after {
  position: absolute;
  right: 18px;
  top: 17px;
  content: "+";
  color: var(--red);
  font-size: 22px;
  line-height: 1;
}

.faq-stack details[open] summary::after {
  content: "−";
}

.faq-answer {
  padding: 0 18px 18px;
  color: var(--muted);
}

.faq-answer p {
  margin: 0;
}

.site-footer {
  padding: 34px 0;
  border-top: 1px solid var(--line);
  background: var(--ink);
  color: #d8dde0;
  text-align: center;
}

.footer-inner {
  width: var(--rail);
  margin: 0 auto;
  text-align: center;
}

.footer-inner p {
  max-width: 900px;
  margin: 8px auto;
  text-align: center;
  font-size: 13px;
}

@media (max-width: 820px) {
  :root {
    --rail: min(100% - 30px, 680px);
  }

  .header-inner {
    min-height: 62px;
  }

  .menu-toggle {
    display: block;
  }

  .site-nav {
    position: absolute;
    left: 15px;
    right: 15px;
    top: 62px;
    display: none;
    padding: 8px;
    border: 1px solid var(--line);
    background: var(--white);
    box-shadow: 0 16px 30px rgba(32, 36, 42, 0.12);
  }

  .site-nav.is-open {
    display: grid;
  }

  .site-nav a {
    border-bottom: 1px solid var(--line);
  }

  .header-download {
    display: none;
  }

  .hero-inner {
    min-height: 0;
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 28px 0 30px;
  }

  .hero h1 {
    font-size: 36px;
  }

  .hero-copy > p {
    margin-top: 14px;
    font-size: 15px;
  }

  .hero-actions {
    margin-top: 18px;
  }

  .mode-row {
    margin-top: 18px;
  }

  .instrument-frame {
    min-height: 314px;
  }

  .instrument-frame::before {
    width: 260px;
    height: 260px;
  }

  .instrument-frame::after {
    width: 304px;
    height: 304px;
  }

  .instrument-frame img {
    width: 166px;
    border-width: 5px;
  }

  .dial-index {
    width: 82px;
    font-size: 10px;
  }

  .snapshot-inner {
    grid-template-columns: 1fr;
  }

  .snapshot-band h2 {
    margin-bottom: 16px;
  }

  .snapshot-item {
    padding: 12px 0;
    border-left: 0;
    border-top: 1px solid #515860;
  }

  .section {
    padding: 58px 0;
  }

  .section h2 {
    font-size: 29px;
  }

  .path-grid,
  .feature-grid,
  .gallery-strip,
  .faq-preview,
  .page-hero-inner,
  .article-layout {
    grid-template-columns: 1fr;
  }

  .path-step {
    min-height: 0;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .path-step:last-child {
    border-bottom: 0;
  }

  .gallery-strip {
    gap: 34px;
  }

  .screen-item img {
    width: min(100%, 336px);
    margin: 0 auto;
  }

  .faq-preview {
    gap: 30px;
  }

  .cta-inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .page-hero {
    padding: 46px 0 42px;
  }

  .page-hero-inner {
    gap: 26px;
  }

  .page-hero h1 {
    font-size: 36px;
  }

  .article-layout {
    padding: 42px 0 64px;
    gap: 34px;
  }

  .article-nav {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }

  .article-nav a {
    padding-right: 12px;
  }

  .guide-rail {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 430px) {
  .brand img {
    width: 34px;
    height: 34px;
  }

  .hero h1 {
    font-size: 32px;
  }

  .page-hero h1 {
    font-size: 29px;
  }

  .hero-actions {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }

  .instrument-frame {
    min-height: 292px;
  }

  .instrument-frame img {
    width: 152px;
  }

  .section-heading {
    align-items: flex-start;
    flex-direction: column;
    gap: 8px;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .feature-item {
    min-height: 0;
  }

  .cta-inner h2 {
    font-size: 26px;
  }
}